William Byrne

William, Bill or Billy Byrne may refer to:


 * William Byrne (boxer), former boxer from New Zealand
 * William Byrne (Catholic) (1780–1833), Irish missionary and educator
 * William Byrne (engraver) (1743–1805), British artist
 * William Byrne (painter) (1906–1997), American painter
 * William Byrne (priest), Irish priest
 * William A. Byrne (1872–1933), Irish poet and educator
 * William D. Byrne Jr., United States Navy admiral
 * William Draper Byrne (born 1964), Roman Catholic bishop of Springfield, Massachusetts, United States
 * William Henry Byrne (1844–1917), Irish architect
 * William Matthew Byrne Sr. (1896–1974), American judge
 * William Matthew Byrne Jr. (1930–2006), American judge, and son of William Matthew Byrne Sr
 * William Michael Byrne (1775–1798), Irish revolutionary
 * William Patrick Byrne (1859–1935), member of the British Civil Service
 * William Pitt Byrne (1806–1861), British newspaper editor and proprietor of The Morning Post
 * William T. Byrne (1876–1952), American politician in New York
 * Bill Byrne (athletic director), American collegiate athletic director
 * Bill Byrne (footballer, born 1896) (1896–1930), Australian footballer for Fitzroy
 * Bill Byrne (footballer, born 1931) (1931–2020), Australian footballer for Melbourne
 * Bill Byrne (politician) (born 1958), Member of the Queensland Parliament
 * Bill Byrne (sports entrepreneur) (1936–2007), founder of the first women's professional basketball league
 * Billy Byrne (footballer) (1918–2001), English footballer
 * Billy Byrne (hurler) (born 1960), Irish retired hurler